Popcorn Stitch

Intermediate Textured

A group of complete double crochets worked into one stitch, then folded and closed to pop forward off the fabric.

Work to the stitch where the pattern calls for a popcorn.
Work 4-5 complete double crochet stitches, not unfinished ones, all into the same stitch.
Remove your hook from the working loop, then insert it front-to-back through the top of the first double crochet you made in that group.
Pick up the working loop again and pull it through the top of that first stitch.
Chain 1 to close and hold the popped shape in place, then continue in pattern.

Unlike bobble or cluster stitch, popcorn is built from fully completed double crochets, then folded together afterward — that's what gives it a crisper, more defined pop than a bobble.
Popping the group toward the right side of the fabric, rather than letting it sit flat, is what gives popcorn stitch its 3D, raised look.
Popcorns pull the surrounding fabric in, similar to bobbles — space them with a few plain stitches between to avoid excessive puckering.